Rotary cover mechanism for portable electronic devices

1. A rotary mechanism, comprising: a base defining a recess and a positioning post formed in the recess, an imaginary central line of the recess being colinear with an longitudinal axis of the post; a cover rotatably mounted to the base; a torsion spring, two ends of the torsion spring fixed to the base and cover respectively; a locking module including a spring and a locking member, the spring having a longitudinal axis co-linear with the imaginary central line of the recess and the longitudinal axis of the positioning post and received in the recess and placed around the positioning post, the locking member positioned on the spring and abutting against the cover, the locking member limiting the cover rotation relative to the base; wherein when the cover overcomes the limitation of the locking module, the cover automatically rotates relative to the base due to the torsion spring.

2. The rotary mechanism as claimed in claim 1 , wherein the cover defines a concave depression, one end of the locking member resists the spring, and the other end of the locking member is received in the concave depression.

3. The rotary mechanism as claimed in claim 2 , wherein the locking member has a seat, a bulge is formed on a top surface of the seat, and a containing groove is defined in a bottom surface of the seat, one end of the spring is received in the containing groove, and the bulge is received in the concave depression.

4. The rotary mechanism as claimed in claim 3 , wherein a clasp is respectively formed at two sides of the seat, a protrusion is formed on the base corresponding to the recess, the protrusion includes a bottom wall and four sidewalls, two opposite sidewalls of the protrusion respectively define an opening communicating with the recess, and each clasp is through the recess, and is engaged in a corresponding opening.

5. The rotary mechanism as claimed in claim 1 , wherein the cover defines a receiving hole, and the base forms a sleeve, the sleeve is rotatably received in the receiving hole.

6. The rotary mechanism as claimed in claim 5 , wherein the sleeve defines a pin hole, the cover forms a fixing portion, one end of the torsion spring is locking in the pin hole, and another end of the torsion spring is locking in the fixing portion.

7. The rotary mechanism as claimed in claim 6 , wherein the fixing portion includes a bottom board and two side boards, the bottom board defines a pivot hole.

8. The rotary mechanism as claimed in claim 1 , wherein the torsion spring has a first end portion and a second end portion, the first end portion is bent in a radial direction, and the second end portion is bent in an axial direction and further bent in a radial direction.

9. The rotary mechanism as claimed in claim 1 , wherein the base defines a sliding groove, the cover forms a block, the block slidably received in the sliding groove.

10. The rotary mechanism as claimed in claim 1 , further comprising a cushion positioned between the cover and the torsion spring.

11. A portable electronic device, comprising: a base defining a recess and a positioning post formed in the recess; a cover rotatably mounted to the base; a torsion spring, two ends of the torsion spring fixed to the base and the cover, respectively; a locking module including a spring and a locking member, the spring received in the recess and placed around the positioning post, the locking member positioned on the spring and abutting against the cover, the locking member limiting the cover rotation relative to the base; wherein when the cover overcomes the limitation of the locking module, the cover is automatically rotated relative to the base due to the torsion spring.

12. The portable electronic device as claimed in claim 11 , wherein the torsion spring has a first end portion and a second end portion, the first end portion is bent in a radial direction, and the second end portion is bent in an axial direction and further bent in a radial direction.

13. The portable electronic device as claimed in claim 11 , wherein the base defines a sliding groove, the cover forms a block, the block is slidably received in the sliding groove.

14. The portable electronic device as claimed in claim 11 , further comprising a cushion, wherein the cushion positions between the cover and the torsion spring.

15. The portable electronic device as claimed in claim 11 , wherein the cover defines a concave depression, one end of the locking member resists the spring, and the other end of the locking member is received in the concave depression.

16. The portable electronic device as claimed in claim 15 , wherein the locking member has a seat, a bulge is formed on a top surface of the seat, and a containing groove is defined in a bottom surface of the seat, one end of the spring is received in the containing groove, and the bulge is received in the concave depression.

17. The portable electronic device as claimed in claim 16 , wherein a clasp is respectively formed at two sides of the seat, a protrusion is formed on the base corresponding to the recess, the protrusion includes a bottom wall and four sidewalls, two opposite sidewalls of the protrusion respectively define an opening communicating with the recess, and each clasp is through the recess, and is engaged in a corresponding opening.

18. The portable electronic device as claimed in claim 11 , wherein an imaginary central line of the recess is colinear with an longitudinal axis of the post, and the spring has a longitudinal axis co-linear with the imaginary central line of the recess and the longitudinal axis of the positioning post.